AB0617 High prevalence of osteoporosis and fragility fractures in patients with ANCA-associated vasculitis: a cross-sectional study
Authors: P. Delvino, S. Monti, G. P. Grieco, E. Bozzalla Cassione, G. Franchi, L. Bogliolo, C. Montecucco
Journal: Annals of the Rheumatic Diseases (2022)

Background The advent of effective immunosuppressive treatments significantly improved the prognosis of ANCA-associated vasculitides (AAV), which have become chronic relapsing diseases. Patients with inflammatory rheumatic disorders are particularly prone to reduced bone mineral density (BMD) and fragility fractures (FF), due to chronic glucocorticoid therapy, immunosuppressant-induced hypogonadism, systemic inflammation, functional disability and comorbidities. At present, there is paucity of data concerning the risk of osteoporosis and FF in AAV. Objectives To describe the occurrence of osteoporosis and major FF in a cross-sectional cohort of patients with AAV. Methods Patients diagnosed with granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA), according to ACR criteria and/or Chapel Hill definitions and regularly followed-up in our vasculitis center were included. BMD was measured by dual-energy X-ray absorptiometry (DEXA) of the proximal femur and lumbar spine, between March 2016 and September 2021. Osteoporosis was defined by a T-score below –2.5 SD, whereas osteopenia was defined by a T-score between -1 and -2.5 SD, according to the World Health Organization criteria. Vertebral fractures were assessed by X-ray of the dorso-lumbar spine. Data on previous osteoporotic hip fractures were collected. Results Sixty-two consecutive patients were included (59.7% female, mean age at time of DEXA 61.8±10.5 years, disease duration 97.0±76.1 months). Sixteen (25.8%), 8 (12.9%) and 38 patients (61.3%) were affected by GPA, MPA and EGPA, respectively. BMD findings indicating osteoporosis and osteopenia, at either the lumbar spine and/or the proximal femur, were observed in 15 (24.2%) and 39 patients (62.9%), respectively, whilst only 8 patients (12.9%) had normal BMD values at both sites. Fifteen patients (24.2%) reported 51 major FF (50 vertebral fractures, 1 hip fracture) during follow-up, with multiple major FF being recorded in 10 patients (16.1%). Osteoporosis, at least at one site, was frequent not only in post-menopausal women (19.4%), but also in 6 males (24%), 3 pre-menopausal women (50%) and 3 patients under 50 years of age (37.5%), respectively (Figure 1). Similarly, major FF occurred in 4 males (16.7%), 1 pre-menopausal female (16.7%) and 1 patient under 50 years of age (12.5%), respectively (Figure 1). Patients with osteoporosis presented a lower body mass index (BMI) (23.1±4.1 vs 25.9±4.4, P=0.03) and a higher prevalence of major FF (53.3% vs 14.9%, P=0.003) compared to patients without osteoporosis. Compared to patients without major FF, those affected by major FF were older (68.8±1.8 vs 59.4±9.3 years, P=0.003), had a higher disease duration (146.9±78.8 vs 81.8±68.9 months, P=0.003) and presented with lower proximal femur BMD values (0.657±0.122 vs 0.761±0.127 g/cm 2 , P=0.007) and proximal femur T-score (-2.0±0.9 vs -1.4±0.8 SD). Notably, 7 out 15 patients with FF (46.7%) did not exhibit BMD findings of osteoporosis. Other variables, including sex, disease subtype, ANCA status, chronic kidney disease or treatment with cyclophosphamide were not related to bone loss or FF. Figure 1. Proportion of patients with osteopenia, osteoporosis and major fragility fractures stratified according to sex, menopausal status and age. Conclusion Patients with AAV are particularly susceptible to BMD loss and fractures, with osteoporosis and major FF being reported in about a quarter of patients. Short-term and long-term monitoring for reduced BMD and FF is warranted in all patients with AAV, including male patients, premenopausal females and those under 50 years of age. Disclosure of Interests None declared